As shown, for example, in FIG. 7, a semiconductor light emitting device emitting blue type light by the prior art is formed by forming a semiconductor lamination portion 36 on a sapphire substrate 31. The semiconductor lamination portion is formed by laminating a low temperature buffer layer 32 made of GaN or the like, an n-type layer 33 made of GaN or the like, an active layer (light emitting layer) 34 made of, for example, an InGaN based compound semiconductor (which means that a ratio of In to Ga can be varied variously and the same applies hereinafter), which has a smaller band gap energy than that of the n-type layer 33 and decides a wavelength of emitting light, and a p-type layer 35 made of GaN or the like. And a p-side (upper) electrode 38 is provided on a surface interposing a light transmitting conductive layer 37, and an n-side (lower) electrode 39 is provided on a surface of the n-type layer 33 exposed by etching a part of the semiconductor lamination portion 36. In this structure, a semiconductor layer having still larger band gap energy such as an AlGaN based (which means that a ratio of Al to Ga can be varied variously and the same applies hereinafter) compound or the like may be employed on the active layer side of the n-type layer 33 and the p-type layer 35 in order to increase an effect of carrier confinement.
When the n-type layer 33 which is a lower semiconductor layer of the semiconductor lamination portion 36 is exposed by etching a part of the semiconductor lamination portion 36 in order to form the n-side electrode 39, etching is carried out at a region of a width A surrounding the chip at the same time as shown in FIG. 7. Such etching at the surrounding region of the chip is carried out for separating light emitting layer forming portions into chips by a dry etching process not so as to occur with cracks or the like in the light emitting layer because it is difficult to dice or scribe nitride semiconductor layers due to its hardness. Therefore, taking into account a tolerance such as a positional displacement or the like on a dicing process of a substrate, the width A of the surrounding region of the chip is approximately 25 to 40 μm in case of a chip size B of approximately 400 μm.
On the other hand, nitride semiconductor also has a refractive index of approximately 2.5 far larger than 1, which is that of air, as same as other compound semiconductor. Therefore, light which is generated in the light emitting layer of the nitride semiconductor layer and travels toward outside easily reflects totally at the boundary between the semiconductor lamination portion and air, and much of the light is not taken out of the semiconductor lamination portion, but is apt to repeat total reflection and attenuates within the semiconductor lamination portion, and as a result, efficiency of taking light out becomes remarkably low such as an order of 10%. In order to solve such problem, there has been introduced an idea, shown in, for example, FIG. 8, in which unevenness is formed on circumferences of a chip so as to make light from a semiconductor lamination portion easy to radiate outside, in compound semiconductor such as GaP based, AlGaInP based, AlGaAs based, or the like (cf. for example PATENT DOCUMENT 1). Namely, as shown in FIG. 8, a semiconductor lamination portion 44 is formed by growing epitaxially an n-type GaP layer 42 and a p-type GaP layer 43 on an n-type GaP substrate 41, and a p-side electrode 46 having a structure of three layers is formed on a surface thereof, an n-side electrode 47 on a back surface of the GaP substrate 41. And after dicing into chips, the unevenness 44a is formed on a surface of an LED chip by a surface-roughening treatment of etching with, for example, hydrochloric acid.    PATENT DOCUMENT 1: Japanese Patent Application Laid-Open No. 2000-299494